Killer T cells, also known as cytotoxic T lymphocytes, are a type of white blood cell that play a crucial role in the immune system. They are responsible for identifying and destroying infected or cancerous cells in the body. These cells recognize specific antigens presented on the surface of infected cells, allowing them to target and eliminate threats effectively. Once activated, killer T cells release toxic substances that induce cell death in their targets. This process helps to prevent the spread of infections and maintain overall health. Their ability to remember past infections also contributes to long-term immunity, making them essential for the body's defense mechanisms.